EUV Patterning Surface Biasing to Prevent Particle Deposition
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Solution Overview
Problem
Contaminant particles are attracted to the positively charged patterning surface in EUV lithographic systems, leading to imaging errors and reduced yield due to electrostatic forces, which existing technologies have not effectively addressed.
Innovation Solution
A patterning device voltage biasing system applies a negative bias voltage to the patterning surface to repel contaminant particles, using a conductive member that can transition between non-contacting and contacting arrangements to ensure reliable voltage application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a patterning surface is electrically isolated from a grounded frame (to maintain electrical stability), then the patterning surface becomes positively charged due to electron ejection, but this positive charge attracts negatively charged contaminant particles, leading to deposition on the patterning surface
Solution Approach 1:
A conductive member is introduced as an intermediary between the voltage source and the patterning surface. This conductive member can be positioned in non-contacting arrangement (maintaining electrical isolation and stability) or transitioning to contacting arrangement (applying negative bias voltage to repel contaminant particles). The conductive member acts as a mediator that allows controlled electrical connection without direct permanent contact.
Solution Approach 2:
The conductive member is configured to transition between non-contacting and contacting arrangements with the patterning surface. This dynamic positioning allows the system to switch between maintaining electrical stability (non-contacting) and applying voltage bias to prevent contamination (contacting), thereby adapting to different operational requirements.
2Object-affected harmful factors
If a voltage source is permanently connected to the patterning surface (to maintain negative bias voltage), then contaminant particles are repelled, but the system complexity increases and electrical stability may be compromised
Solution Approach 1:
The conductive member transitions between non-contacting and contacting arrangements, providing voltage bias only when needed. This dynamic approach reduces system complexity compared to a permanently connected system, as the conductive member can be retracted to a non-contacting position when voltage application is not required.
Solution Approach 2:
The conductive member serves as a controllable intermediary that enables voltage application only when positioned in contacting arrangement. This on-demand voltage application reduces the need for complex permanent electrical connections and control systems, thereby reducing overall system complexity.
3Reliability
If the conductive member is in non-contacting arrangement (to maintain electrical isolation), then electrical stability is preserved, but reliable voltage application to the patterning surface cannot be ensured
Solution Approach 1:
The conductive member can dynamically transition from non-contacting arrangement (preserving electrical stability) to contacting arrangement (ensuring reliable voltage application). This dynamic capability allows the system to achieve both electrical stability and voltage application reliability at different times as needed.
Solution Approach 2:
The conductive member is positioned in non-contacting arrangement during normal operation to maintain electrical stability. When voltage application is needed, it transitions to contacting arrangement. This preliminary positioning in non-contacting state ensures electrical stability is maintained unless voltage application is specifically required.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively prevents contaminant particle deposition on the patterning surface, enhancing the yield of the EUV lithographic process by maintaining a stable voltage and minimizing particle accumulation.
Implementation Method 1
A patterning device voltage biasing system applies a negative bias voltage to the patterning surface to repel contaminant particles
Implementation Method 2
the EUV radiation incident on the patterning surface causes electrons to be ejected from the surface
Implementation Method 3
using a conductive member that can transition between non-contacting and contacting arrangements to ensure reliable voltage application
Data Source
AI summary
A patterning device voltage biasing system for use in a lithographic apparatus, the patterning device voltage biasing system comprising: a patterning device configured to impart a pattern to a beam of radiation, the patterning device comprising a patterning surface with a pattern thereon; and a voltage source, wherein the patterning device voltage biasing system is configured such that a voltage can be applied to the patterning surface of the patterning device by the voltage source.